Selecting the ideal plastic material for your rigid food packaging can be quite daunting. With a wide range of options available, processors must meticulously evaluate factors such as performance, functionality, product protection, and cost-effectiveness to determine the best fit for their packaging needs. Additionally, new regulations focused on sustainable packaging and recyclability have further narrowed the choices, making it even more crucial to choose wisely for single-use plastic applications.
With a myriad of options available, how can brand owners and converters determine the ideal packaging material that meets the processing, performance, and business requirements for their food products? In this blog series, we'll delve into the characteristics of popular rigid plastic food packaging materials, examining both the advantages and disadvantages of one prevalent choice – Polyethylene Terephthalate (PET). Keep reading to discover 6 essential attributes of PET to consider when choosing a rigid plastic food packaging material for your upcoming project.
PET Packaging Material for Beverage Bottles
Polyethylene terephthalate (PET) is a versatile polymer created through the polymerization process involving ethylene glycol and terephthalic acid. PET's primary end-use applications are for packaging and textile manufacturing.
Among various uses, beverage bottles represent the largest market for PET packaging. PET is the leading polymer for packaging carbonated soft drinks and mineral water, and it is increasingly being used for packaging fruit juices, sports and isotonic drinks, ready-to-drink teas, milk, and certain alcoholic beverages. Numerous material properties and characteristic including durability, mechanical strength, and transparency have made it an ideal choice for single-use carbonated beverage bottles.
The Dominance of PET in Food Packaging
PET stands out as the leading material in the creation of rigid plastic packaging, anticipated to account for 36.8% of consumption in 2023 according to the Smithers report “The Future of Rigid Plastic Packaging to 2028.” Trailing behind are PE at 26.1% and PP at 24.2%. In 2023, the global demand for PET in rigid plastic packaging is expected to hit 24.6 million tons. Moreover, this demand is set to grow at a compound annual growth rate (CAGR) of 3.6% from 2023 to 2028, reaching 29.4 million tons. While growth is projected to reduce due to market maturity in the bottle segment and the continued sustainability trend of light-weighting, a significant opportunity exists for the use of food-grade Post-Consumer Recycled PET materials.
While the primary end-use application for PET in the food & beverage space is beverage bottles, this material has also gained significant market share in the packaging of food products and is used in a range of applications from food service containers, bakery & desserts, meat & deli products and more.
Various Grades of PET Packaging Material
Rigid PET comes in various grades tailored for specific needs & packaging applications:
- Amorphous PET (APET): Commonly used for producing sheet and rollstock for thermoformed containers, APET is appreciated for its excellent optical properties, mechanical strength, and superior barrier attributes.
Crystalline PET (CPET): Featuring a partially crystalline structure, CPET excels in high-temperature stability. Typically produced in black, it is used to manufacture sheet and rollstock for thermoformed containers capable of withstanding high-heat applications, including dual-ovenable (up to 400°F for 30 minutes) and microwavable uses.- Glycol-Modified PET (PETG): This high-clarity co-polyester boasts impressive stiffness and impact strength, making it a popular choice for medical thermoformed applications.
- Post Consumer/Industrial Recycled PET (PCR-PET or PIR-PET): Derived from post-consumer (PCR) or post-industrial (PIR) recycled materials, rPET is often blended with virgin PET to enhance the recycled content of packaging.
- Bottle Grade: Ideal for creating injection molded pre-forms and blow molded bottles, this grade is prized for its high transparency.
Additionally, innovative bio-based PET packaging materials are currently under development, promising a more sustainable future for rigid packaging.
The Functional Benefits of PET Packaging Material
FDA approved food contact grades of PET have gained popularity in rigid food packaging due to the excellent functional, performance and aesthetic properties it offers. PET is a very strong material and doesn’t break or fracture, providing adequate protection for food products along the supply chain. In addition, this material has good oxygen permeability properties, which can be beneficial for product preservation. Moreover, this material offers glass-like clarity & transparency, allowing for viewing of the food product or beverage. As for chemical properties, PET offers excellent resistance to alcohols, aliphatic hydrocarbons, oils, grease and diluted acid and moderate resistance to diluted alkalis, aromatic & halogenated hydrocarbons. While PET has a lower heat resistance than other polymers like polypropylene, specialty graces of PET, known as CPET can offer a wider temperature range for microwave applications.
Processing Methods for PET Packaging Material
Polyethylene terephthalate can be easily processed by injection molding and extrusion. It is generally extruded to produce films and sheets and can be later thermoformed. Blow molding is generally used to produce transparent bottles. – Extrusion, thermoforming, injection molding, blow molding & 3D printing
Polyethylene terephthalate (or poly(ethylene terephthalate), PET, PETE, or the obsolete PETP or PET-P), is the most common thermoplastic polymer resin of the polyester family and is used in fibres for clothing, containers for liquids and foods, and thermoforming for manufacturing, and in combination with glass fibre for engineering resins.
Recyclability of PET Packaging Material
With increasing concerns about plastic waste, numerous organizations are striving to create actionable guidelines and standards for designing recyclable packaging that can be used by packaging manufacturers and brand owners to ensure their packaging is in-line with industry-wide sustainability goals & targets as well as changing legislation. For a material to qualify as recyclable, at least 60% of consumers must have access to recycling programs that collect the material for recycling. Additionally, there needs to be a viable market for the recycled material, and the material or product must be capable of being accurately sorted and processed at a material recovery facility.
Clear PET (RIC #1) has been classified as APR Design Preferred, and is considered "Widely Recyclable" by How2Recycle, indicating at least 60% of the population has access to PET recycling programs and can be recycled at-scale. Marked with the Resin ID Code (RIC) #1, PET bottles and jars are widely accepted by almost all recycling programs across the US and Canada. According to the 2022 PET Recycling Report from the National Association for PET Container Resources (NAPCOR), PET recycling rates have reached 29% in the US and 37.8% in North America. Given the extensive use of clear PET in the bottling industry, there's a well-established recycling stream for post-consumer recycled (PCR) PET obtained from recycled bottles. In 2018 alone, almost 2 billion pounds of PET bottles were collected for recycling, and the demand for recycled PET remains robust.
However, while clear PET is seen as a highly valuable material from a recycling perspective, the addition of design features to PET packaging such as opaque pigments and barrier materials or even differences in intrinsic viscosity may render the material non-recyclable due to the potential for contamination of the clear PET recycling stream. Moreover, while PET bottles are highly recycled, recycling of PET thermoforms presents its own set of challenges and only a mere 9% of these products are being recycled.
